Undertale - Regretted Reset
by pukapi
Summary: An involuntary Genocide Run haunts Frisk even way after completing a new True Pacifist Route. Sans listens to their story. Will their friendship remain the same afterwards?
1. Midnight Talk

It was what someone would assume to be nighttime in the Underground. Snowdin Town lay in peace, most of its citizens already in bed and fast asleep.  
The house at the end of the street, however, was still lit up. In one of the rooms upstairs, Sans was still up. Sitting on a chair next to his brothers bed, reading him the end of his good night story.

"and with that, the fluffy bunny hopped home, ready to see his friend again the next day. the end." he finished, closing the book. Papyrus was asleep already, snoring slightly with his unique laugh.

Sans put the book back in its shelf and opened the door to return to his own room.  
Stepping outside, he heard sniffling in the living room. It was very soft, but it was there. He took the stairs that led down and switched on the lights. With a small gasp, he spotted Frisk sitting on the sofa, face buried in their hands and their whole body trembling.

"hey kiddo. what are you doin' down here?" he asked and placed himself next to the child. Frisk just continued to sob but leaned against the skeleton, wrapping their arms around him.  
"I'm sorry... so, so sorry... please believe me." they whispered. Sans seemed confused for a moment.

"what are you sorry 'bout? what happened anyway?" he questioned, petting their head. Frisk sniffed one last time before looking up at him. "N-nothing really. I just had a bad dream. R-really nothing to worry about."

They lied and Sans knew but he decided to play along. "c'mon kid. y'know you can tell me, right? i'm not gonna hurt you." he said with a softer grin. Then silence came over the two of them before Frisk spoke up again.

"But you would if I killed everyone, right? I mean, even if it is not my fault..." Sans' grin disappeared as much as it could. _is the kid talkin' 'bout what happened?_ "is that what you were dreamin' 'bout?" Frisk nodded.

Should they tell him? Would he be able to understand it? Frisk was not sure.

"I mean it kind of IS a bad dream, but on the other hand it's NOT but it's really complicated and... you probably would not believe me if I told you..." Frisk kept their head low. Sans hesitated for a bit and then... "try me, bucko! you can trust me, you know that."

"Huh?!" Frisk seemed confused. "tell me and i will try my best to understand, alright?"

Frisk said nothing, just thinking to themselves if it was the right thing to do. Their heart kept pounding in their chest, stronger and stronger with each passing moment. It almost hurt, but of course the pain was nothing compared to what happened in their 'dream'. And knowing that, they were filled with determination to tell Sans the truth.

"Okay, I'll try and keep it simple... I, uh, I.. have a special ability that allows me to RESET. It's like, uhm... jumping back in time? Yeah, time travel seems closest to resetting, but only to the past. I have this power because of my DETERMINATION. I can also LOAD and SAVE." They paused, letting Sans take the information in.

"so... like in a video game?" The skeleton asked. Frisk giggled. "Kind of. Sounds crazy, doesn't it?"

"nah. sounds pretty cool. well, not as cool as papyrus, but you know what i mean." Sans shrugged.  
"Of course I do." Frisk said with a slight smile.

"wanna tell me more now?" Sans asked. Frisk took a deep breath and exhaled with a sigh.  
"Alright, I guess I don't have a choice now that I started." They said. "I, uhm... I had this 'run' before. The 'True Pacifist Run'. I befriend everyone and get my 'Happy Ending', as Flowey calls it.  
"Every monsters dream comes true and we get to the surface. We lived like this a couple of months and were just happy. I had a new home with Toriel as my mom. I got to see you, Papyrus, Undyne, Alphys and everyone else every day. No worries and I even got Flowey to be my 'friend' in a way. And mom allowed him to stay with us. Then one day, Flowey and I were talking about the time in the Underground."


	2. What happened back then

Frisk was sitting at the dining table in the living room. Toriel was in the kitchen next door, baking another butterscotch-cinnamon pie for dessert later.  
Flowey was in his flower pot, nicely decorated with a green bow by Frisk, on the table in front of the human. Both of them were looking at a photo album, filled with pictures taken by Alphys' security cameras.

Frisk looking directly at the bush camera in Snowdin Forest, their first meeting with the skelebros, fighting and befriending Undyne and a lot more. Even pictures that were more recent after getting to the surface, like their first 'family' Christmas, the whole gang smiling at the camera.

Frisk explained the pictures to Flowey while pointing at them.  
"And that's when Undyne and I were trying to cook and we accidentally set her house on fire. Surprisingly, she wasn't even mad, as if that happened a lot." Frisk chuckled at the memory of Undyne looking at the child dumbfounded as they were literally petting the vegetables.  
"Uh huh..." Flowey said in a bored tone, but looked at the pictures with a spark of interest in his expression.

"Sometimes I wish I could go back and do it all again..." Frisk said with a content smile, while looking at a picture of Mettaton and them posing dramatically.  
"You know you can do that, right? You just have to-" Flowey started with his creepy face, but was sprayed with water before he was able to finish his sentence.

"NO!" The human said in a serious tone.  
"You know I am against that!" They lectured the yellow flower.

"Oh my god, Frisk! I was kidding. Jeez..." The plant complained.  
"You shouldn't joke about something this serious. I like how everything turned out. I wouldn't want to change anything about how my life is now."  
"I know that..." Flowey said and his face fell a little. "I know YOU won't reset... The only thing I'm worried about is... _her_..."

"Who are you talking about?" Frisk asked confused. "I'm talking about... **_Chara_**." Flowey whispered.

"Why? You told me she died, right? So why would you worry about her now?" Frisk questioned.  
"I know what I told you, **IDIOT!** " Flowey shouted, causing the human to flinch.

"It's just..." He started calmer. "Even though she's been dead for a while now, I can't shake off the feeling of still being watched. It feels like a ghost is following you everywhere you go. This is one big point why I refused to live with you and Toriel at first. I feel like something bad is going to happen if I'm too close to you." He murmured the last part more to himself, but Frisk understood anyways.

"Don't worry, Flowey." They said confidently. "It's probably just paranoia. Nothing can happen to you. Dead people don't come back."  
"Yeah, guess you're right, ain'tcha? To be honest... I feel a lot safer and more comfortable living here with you and mo- **Toriel!** " He corrected himself.

Frisk pretended not to notice his little slip-up and flipped the album to the, up until now, last page. It showed the group picture that was taken after everyone reached the surface, making Frisk happy and reminding them what they had done for everyone to reach this point in their life.

"Frisk, my child. Would you please come to the kitchen? Dinner is almost done!" Toriel called, standing at the kitchen door and looking at them with gentle eyes.

"Coming, mom!" Frisk called back. Grabbing Flowey, closing and leaving the book on the table, they ran to the kitchen to help Toriel with the rest.  
What they didn't notice was a small person, a child, appearing in the empty living room. The girl walked over to the table and looked at the book with disgust and a grin on her face.

"My,my, my... What a nice child you are, dear Frisk. Not wanting to hurt even a single little soul... Let us see what we can do about that problem!" She giggled and opened the page with the group picture before crossing out every face with a red marker. She then closed the album and disappeared without a trace, like she never stood in the room in the first place.

Later that night, after Frisk went to bed, Flowey stayed up a little longer, thinking about his conversation with the human.

 _That little idiot doesn't know what they are saying... Sure, Chara is dead but she's still here. I can still feel her presence.  
_ With those last thoughts, Flowey closed his eyes.

As the clock hit midnight, little footsteps were heard walking through the house. Flowey, being a light sleeper, woke up immediately. He looked around, spotting Frisk still in bed and fast asleep.  
The door creaked open and now that person stood inside the room, the green sweater was unmistakable. The colors Asriel and his adopted sibling shared.

"C-Chara..." Flowey whispered to himself, seeing the girl approach the bed and nightstand.  
He tried to hide by covering himself with his petals. Of course he knew that this method wouldn't work. He could still feel her blood-red eyes on his back.

"Asriel... Why are you hiding from me?" She asked, petting the flower carefully. Her voice was cold as ice and Flowey could practically _hear_ her smirking.

"W-what are you doing here? Why did you come back?" The flower whimpered. shaking every time she stroke his petals lightly.  
"I am just visiting my family. Is that a crime? I don't think so. In my opinion, the real crime is that said family _**REPLACED ME!**_ " Chara yelled, her hand now pressing down on the poor flower.

Flowey looked over to Frisk, wondering how they could sleep with the noise around them.  
"Don't you worry about them, dear prince. They can't hear me. Like everyone else in this house. After all, I am just an imagination, right? Because you are paranoid that I will come to haunt you, _right?!_ " Flowey stayed silent. "Thought so..."

"W-what are you going to do now?!" Flowey suddenly asked panicky, seeing chara approach the sleeping Frisk.

"Well, I am going to do what I wanted to for a long time. Those filthy humans are going to pay for what they did... And the best thing? Everyone will think it was dear Frisk over here." She giggled. Flowey looked at her perplexed.

"W-what do you mean? Why do you think-!" He stopped dead, watching Chara as she put her hand on Frisk's forehead, closing her eyes to concentrate.

"Well, I will see you then, dearest brother..." After that Chara vanished with a laugh and the last thing Flowey saw was pure white...

As Frisk woke up, the first thing catching their attention was the bright sunlight coming from above. Next was the flower-covered ground beneath them and the high cavern walls.

Suddenly fully awake. Frisk sat up from their position and looked around hastily.  
 _H-how?! Why am I back here? What happened?! I didn't do that!  
_ Those and other thoughts rushed through their mind as they tried to figure out how a reset was possible without them doing it voluntarily.

"So you are finally awake. Did you sleep well?" A voice, that wasn't familiar to Frisk, said.  
"Who are you?" They asked, trying to stand up, but finding that they were not able to do so.

"Not worth trying any more, Frisk. You are no longer in control. I am... And to your question.. I think you already have an idea. You have never seen me, but heard stories from the monsters down here. The fallen child that became princess and died... What a tragedy.."

"So you are...?" Frisk muttered, putting together the pieces.  
"But how is that possible?! You aren't alive! How can you be back?" They questioned frantically, hearing laughter coming from their body in a girls voice.

"Wow, you **REALLY** are an idiot. I thought he was exaggerating. Asriel told you, didn't he? I mean, I may not be **exactly** a ghost, but I am still here in this world." She explained. Frisk was shocked.

"Well, whatever. Now that that's clarified, let's start with our little trip, shall we?" Chara grinned, standing up from the bed of golden flowers and started towards the gate leading to the ruins.

Frisk. still confused and in a panic, knew what would come next. The encounter with a certain flower, teaching them 'how things work around here'.

However, Flowey seemed to notice that something is off with the human.  
"You know..." He started. "I have a feeling you aren't who you pretend to be. You are someone... Or something.. more sinister." He viewed the human from head to toe and back to look in those blood-red eyes.  
"It actually seems like you aren't really human. No. You're empty inside. Just like me." Flowey finished, grinning.

Chara just watched silently, giving the flower a death glare, causing him to start sweating slightly.  
"We are nothing alike." She spoke quietly, sending shivers down the spines of Flowey and, somehow, Frisk.

"I guess I have to go now." She continued and walked to the gate, not wanting to wait for Toriel to arrive.  
"I've got work to do. I hope we will be able to meet again and maybe... Talk about old times.. _Asriel_.."

And with her last words echoing through the hall, Chara walked off. Laughing, leaving behind a startled Asriel, who finally realized what is eventually going to happen.


	3. Coming clear

Sans watched the kid in great concern. He was shocked by what he had just listened to. Somewhere in the middle of the story, Frisk had snuggled up against the skeleton, seeking comfort while continuing.

"And then she... she just.." Frisk hiccuped. Sans wrapped his arm around the child, trying to soothe them. "let it all out, frisk. what did she do then?" he asked. Frisk burst into another wave of tears.

"She just killed EVERYONE! She rammed her knife into everyone who got in her way!" They cried. "Every Froggit, every Whimsun, every single monster... and mom.." Frisk started whispering. "She didn't show any mercy to ANYONE. And mom still tried to protect her, but Chara wouldn't listen to her. She said something about betrayal and then... just cut her. Right across the chest..."

Sans' eye sockets had become pitch black by now. He couldn't believe what he was hearing from the human. All the time he had thought Frisk was responsible for all the hurt he had felt at the time. He never would have thought that...

"When we got to Snowdin Forest," The kid continued. "we met you and Papyrus. You seemed to notice something was off, at least I hoped so. But Papyrus... he was still his cheerful self, even as Chara ignored all his puzzles. And then you vanished... and I didn't know what to do." Their head hung low.

Sans knew what would come next. He had seen it from afar, but it had been too late to do something.  
"She killed Papyrus..." Frisk whimpered, their body tense and shaking at the same time. "And I couldn't do anything to stop her! I couldn't reach my save! I wasn't in control, juts like she said!"  
They held their head, the images swirling around in their mind.

The skeleton kept quiet, listening to the heartbreaking sobs of the little child next to him.  
How could he have ever thought Frisk was able to kill? He glanced at them, watching them wipe away their never ending tears of regret.

He felt awful.

"I had hoped you were able to help me. But how could you, if you didn't know what I was able to do or what situation I was in?"

"i did." Sans whispered. "Huh? W-what do you mean?" Frisk asked. "i mean... i didn't know about your situation at the time, but... i know about resets. about all your abilities. i just... didn't know what to do about that. i couldn't do anything to stop you..."  
 _Liar._ But he lied _for them_. To not make them feel worse than they already did.

Frisk continued, telling him next about their encounter with Undyne. How she saved Monster Kid and fought as the 'True Hero'. Turning to dust in the end, but trying to stay alive to fight further for the future of the Underground. Failing...

How Alphys evacuated the remaining monsters, Mettaton staying behind to stop Chara.  
"After the fight ended... That's when I finally had hope again to do something." Frisk said. Their cheeks were still wet, but they had managed to bring their tears under control.

"Chara had cut all of Mettaton's circuits. She started talking to me, telling me how much easier it was to just end the Underground than befriending them. She started giggling and laughing loudly... and I saw my only chance. She was always very observant of my behavior but in that moment she was distracted and didn't notice anything. So I reached out and... I reset." Frisk smiled slightly.

"Chara had screamed at me, yelling how I could do such a thing. She seemed... confused and.. lost. Angry and mad."

"whaddya expect, kid? no one would like if their evil plan was foiled."  
"Yes sure. But at that moment she didn't seem evil anymore. I was able to feel tears welling up, like they were my own, but they weren't. But she didn't cry... stayed silent. And after I woke up in the ruins, she was gone. Just vanished and I haven't seen her since."

Sans looked at the child for a moment or two, before wrapping his arm around their shoulders.  
"the important thing is, that it's finally over."  
"You thought I did it... right?"  
Silence.

"yeah..." Sans admitted, ashamed.  
"You don't have to feel bad, Sans. I would've probably not reacted in any other way."

He looked at Frisk skeptically.

"that's nice of you to say, but i'm sure you would. you really are like papyrus when it comes to that. you guys see good in everybody, even if they behave like chara. you always try to find out why they do what they're doin'. the reason that keeps them going. i just can't do that."

"But that's okay. A lot of people can't. You aren't alone in that matter." The child smiled up at their friend.

"i guess so." He grinned back. "ya feelin' better now, kiddo?"  
The human nodded.  
"Yeah, much. Thank you for listening to me... I really needed that.."

"no sweat, frisk. that's what i'm here for."  
Sans stood up, turning to the window behind them to close the curtains.

"alright, buddy. it's way past your _bed time_. you should really go to sleep now."  
"But I'm not tired." Frisk tried to argue.

"well, hey not-tired. i'm the sleep police and i can't have you resist _a-rest_ any further. wouldn't want to wake my partner for help, now would we?"

Frisk giggled. "No, we wouldn't." They hopped off the sofa and skipped towards the stairs.

Sans grabbed his hoodie and started towards the door.  
Frisk, who had reached the upper floor by now, looked through the gaps of the banister.

"Where are you going?" They tilted their head to the side, confused.

"just gonna catch some fresh air. the story _was_ pretty rough and a lot to take in, y'know?"

Frisk frowned.

"hey, don't worry. i'm alright. just go to sleep. paps would take away my ketchup if he knew how long you've been up. so, do me a favor and try not to get any bags under your eyes, y'hear me?"  
He winked at the child, who smiled and rubbed an eye before yawning deeply.

"Alright. Good night, Sans." They waved to the skeleton, who returned the gesture.

Frisk vanished into their room between the ones of the skelebros. It was built by Undyne and Alphys to the humans preferences, with lots of love... the actual kind of love.  
(And also a lot of anime breaks, smashing walls down and the occasional spot of Papyrus' _famous_ spaghetti on the floor...)

After the bedroom door closed, Sans lowered his hand and opened the door in front of himself.  
With a grim expression he stepped outside. Only to be greeted by the presence of another person.

Or... _something..._

Not moving, he stared into those blood-red eyes of the smiling girl opposite to him.

"killer kid..."  
"Comedian..."

 **Hey there. We're actually close to the end already. I wanna thank you guys for over 250 views, I absolutely appreciate it. (That's WAY more than over on Wattpad... am I even allowed to talk about that here? I dunno...)  
But yeah, the next chapter is most likely gonna be the last one. Feel free to leave your thoughts on what you think of the story. I would love to read what you guys have to say. :)  
Pukapi**


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